This paper describes the recent and successful features of the intensive program at Detroit Diesel Allison, Division of GMC, to control the costs of advanced military aircraft gas turbine engines in line with the costs of current production engines and of those produced during the past several years. We have been attempting to incorporate highly advanced technology into our new products, while at the same time holding the costs in line with older technology products. In many instances, we have been able to use the advanced technology to lower costs at the same time that weight and performance are improved. There are examples of this in aerodynamics, mechanical design, and materials and processes. In other instances, the experience is more conventional, in that lower costs involve increases in weight; in these cases, lists of weight increases versus cost decreases are maintained, and the most attractive concepts are incorporated up to the acceptable weight limits of the engine specification.